Federal, state and local authorities have refused to say if Sparkman was at work going to door-to-door for census surveys in the time before his death, but his Census identification tag was found taped to his body.
Jerry Weaver of Fairfield, Ohio, told The Associated Press on Friday that he was among a group of relatives who made the gruesome discovery on Sept. 12.
"The only thing he had on was a pair of socks," Weaver said. "And they had duct-taped his hands, his wrists. He had duct tape over his eyes, and they gagged him with a red rag or something."
"And they even had duct tape around his neck. And they had like his identification tag on his neck. They had it duct-taped to the side of his neck, on the right side, almost on his right shoulder."
Two people briefed on the investigation said various details of Weaver's account matched the details of the crime scene, though both people said they were not informed who found the body. The two spoke on condition of anonymity because they were not authorized to discuss the case.
Weaver said he couldn't tell if the tag was a Census Bureau ID because he didn't get close enough to read it. But both of the people briefed on the investigation confirmed Sparkman's Census ID was found taped to his head and shoulder area.
Weaver said he could see something written on Sparkman's chest but he did not go close enough to read it.
While authorities confirmed for the first time Thursday that asphyxiation was the cause of death, even the details behind that were murky. According to a Kentucky State Police statement, the body was hanging from a tree with a noose around the neck, yet it was in contact with the ground.
Weaver, who works for a family topsoil business in Fairfield, said he was in town for a family reunion and was visiting family grave sites at the cemetery when he and family members including his wife and daughter came across the body.
The scene left Weaver without a doubt how Sparkman died. "He was murdered," he said. "There's no doubt."
Weaver said the body was about 50 yards from a 2003 Chevrolet S-10 pickup truck. He said Sparkman's clothes were in the bed of the truck.
"His tailgate was down," Weaver said. "I thought he could have been killed somewhere else and brought there and hanged up for display, or they actually could have killed him right there. It was a bad, bad scene."
"It took me three or four good nights to sleep. My 20-year-old daughter ended up sleeping in the floor in our bedroom." he said.
Clay County Sheriff Kevin Johnson declined to comment on the investigation because the department is only playing a supporting role but said patrols have increased in the Daniel Boone National Forest since the body was found.
The Census Bureau has suspended door-to-door interviews in the rural county pending the investigation.
Trooper Trosper said it was clear this wasn't a natural death but said all other possibilities were being considered.
"This case has many facets," he said. "To investigate cases, you have to rule out different scenarios. We are not able to rule out many scenarios at this time, and that's what makes this a difficult case."
Although anti-government sentiment was one possibility in the death, some in law enforcement also cited the prevalence of drug activity in the area - including meth labs and marijuana fields - although they had no reason to believe there was a link to Sparkman's death.
"Now they're taking their meth lab operations into the rural, secluded areas," Clay County Sheriff Kevin Johnson said. "We've had complaints in the area, but not that particular location."
Associated Press Writer Devlin Barrett in Washington contributed to this report. Alford reported from Frankfort.